The invention relates to a liquid stabilized plasma burner, and in particular, to a liquid stabilized plasma burner having an improved flexible cathode holder.
During the operation of a liquid stabilized plasma burner, an electric arc exists between the cathode and anode. In order for the liquid stabilized plasma burner to operate successfully, this arc must be continuous. A more detailed description of the general operation of a liquid stabilized plasma burner is found in U.S. Pat. No. 4,338,509 issued July 6, 1982 for a "Process Of And Apparatus For Producing A Homogeneous Radially Confined Plasma Stream". The cathode holder illustrated in U.S. Pat. No. 4,338,509 is typical of the earlier cathode holder.
The earlier cathode holder is of a two-piece construction. One piece is an elongate cylinder of electrically-conductive material having an integral radially extending flange at one end thereof. An arcuate portion of the cylinder between the flange and the other end is removed to form an aperture. A corresponding electrically non-conductive portion or insert covers the aperture. A pair of elastic retainers surround the cylinder and insert to maintain the insert in place. The non-conductive insert occupies approximately 180 degrees of the circumference of the central bore of the cylinder.
As can be appreciated, one primary purpose of a liquid stabilized plasma burner is to coat objects with a coating material. The liquid stabilized plasma burner is maintained stationary and the object to be coated is moved relative to the plasma burner. The object to be coated may be rotating while it is moved in a generally longitudinally axial direction until its entire surface is coated. At this point, the plasma burner is turned off so that another object can be placed in the holder or jig.
When the plasma burner is turned off, there often times is created a severe vibration. Since the rod cathode is elongate and has a meaningful length thereof extending from the cathode holder, this vibration causes the rod cathode to move in a radial direction. The cathode holder that has been utilized heretofore has not always been able to accommodate this movement of the rod cathode so that electrical contact between the rod cathode and cathode holder is broken; and consequently, the electric arc between the cathode and the anode is terminated. As can be appreciated, this is an undesirable consequence.
The severe vibration that accompanies turning off the plasma burner can also cause the rod cathode to break since cathode holders of the past have not accommodated the movement of the rod cathode. If the cathode breaks, the electric arc will be terminated. As mentioned above, the termination of the electric arc is an undesirable consequence.
In order to restart the plasma burner, a portion of the plasma burner must be disassembled and the rod cathode repositioned relative to the cathode holder so that electrical contact exists therebetween. The plasma burner must then be assembled and restarted.
It would thus be desirable to provide a liquid stabilized plasma burner having an improved cathode holder that would maintain electrical contact with the cathode under vibratory conditions.
It would also be desirable to provide a liquid stabilized plasma burner having an improved cathode holder that would maintain electrical contact with the cathode under vibratory conditions in which the cathode moves in any generally radial direction.
It would also be desirable to provide a liquid stabilized plasma burner having an improved cathode holder that would accommodate the movement of the rod cathode during vibratory conditions so as to help prevent breakage of the rod cathode during the vibratory conditions.